In gas metal arc (GMA) welding, also known an MIG welding, an electric arc is established between the workpiece and a consumable bare wire electrode. The arc continuously melts the wire as it is fed to the weld puddle. The weld metal is shielded from the atmosphere by a flow of an inert gas, or gas mixture.
A MIG welding gun has a flexible conduit therein for receiving a consumable welding wire. The welding wire passes from a roll into one end of the flexible conduit and is guided thereby to a welding tip where the wire extends out from such tubular welding tip for use in a welding process. It should be noted that the wire-feed speed determines the arc current. If the wire speed or current becomes inconsistent, it can cause stubbing to the workpiece or burning back to the guide tube (welding tip). Inconsistent wire speed will cause weld penetration, deposition rate, and bead size to be inconsistent.
The welding wire comes on a spool or in a coil. When the wire unwinds, it tends to take the same shape and wind itself back up much like a spring does. When the welding wire is passed through the conduit, the welding wire is being uncoiled, but the wire is still somewhat coiled. This causes friction in the conduit. The welding wire is passing through the conduit at speeds from 100 to 800 inches per minutes. This constant friction causes metal filings and other contaminants to fill the conduit and cause more friction. Dirt and contaminants on the welding wire also add to this problem. This friction and drag on the welding wire causes the wire speed to be inconsistent because the drive rolls start to slip on the wire. This causes stubbing to the workpiece or burning back to the welding tip, resulting in inconsistent weld penetration, inconsistent deposition rate, and/or inconsistent bead size. The welder will spit and sputter and produce a situation where the welding gun does not operate properly. In the past, there have been some proposed solutions to the problems, such as using something to wipe the consumable wire off as it goes into the flexible conduit. Such a solution has not been entirely successful.
In order to solve the aforementioned problem, even when a wiping device is used, once the welding gun becomes inoperative because of contaminants within the flexible conduit, the normal solution is to replace the flexible conduit. This requires considerable time and, of course, expense in purchasing the new part.
Consequently, there is a need for a solution to the aforementioned problem.